Scytophycins are a class of compounds originally derived from blue green algae. Five such compounds ("scytophycins A-E") have been previously disclosed and characterized in U.S. Pat. Nos. 4,996,229 and 4,863,955.
Scytophycins A-E have been known to exhibit antineoplastic properties. Nevertheless, neoplastic disease continues to be a widespread problem and the majority of malignant neoplasms remain refractory to treatment. Thus, there is a continuing need for new antineoplastic agents useful either in treatment of human cancer or because they contribute to a general understanding of the underlying mechanisms by which malignant cells proliferate.
Scytophycins A-E also have been shown to inhibit fungal pathogens known to cause a variety of human disease conditions. In addition, fungal plant pathogens cause significant economic losses to agriculture each year. New compounds which are effective against fungal pathogens are needed to treat disease conditions which remain refractory to prior treatment techniques. It is further desirable to provide new antifungal compounds to inhibit fungal strains which may develop resistance to existing fungicides.
While the scytophycins A-E have been known to be useful as antineoplastic and antifungal agents, their modes of affecting cellular processes has not been previously described or understood. The lack of understanding about how scytophycins inhibit cellular processes has limited their use for other applications.
The study of cellular processes in normal and abnormal cells can lead to greater knowledge of disease conditions or to methods useful in manipulation of cells in a manner useful in medicine or agriculture. New chemical agents which interfere with cellular processes are useful in the study of cell structure, function, and reproduction.
For example, cytochalasins, derived from fungi, have been found to have specific effects on living cells. Numerous research studies have been conducted using cytochalasins because of their ability to disrupt cellular processes. Cytochalasin B is now known to inhibit microfilament formation by binding to the end unit of growing actin microfilaments and preventing their assembly. Cytochalasins are useful in the biotechnology industry, particularly for production of monoconal antibodies from hybridomas which are valuable tools in medicine, research and industry.
One side effect of using cytochalasin B which is sometimes undesirable is that it inhibits cellular sugar uptake. Further, there is a need for other inhibitors of microfilament formation, which are more stable, more soluble, and more potent than cytochalasin.